What should you do with keno’s ‘odd’ ball?

May 21, 2002 4:47 AM


So, you notice that a number has not come up in quite a while, perhaps 25 or even 50 games. We know from our mental excursion last week that we should not play this number ”” not for any reason.

But if you don’t play this number, but play the others, you will have an edge ”” not a large one, but it’s real nonetheless. The other players, less observant than you will not have this edge. Thus an ethical question arises: Should you report this?

I say yes. If I should see this situation arise, and I was confident that the keno game was on the up and up, that the situation is merely the result of an unfortunate error, I would report this to the keno manager. Once reported, I would expect that the game would take immediate action to correct the fault. If this did not happen, I would call the Gaming Control Board.

For the casino and the keno game, a missing ball is a wash in a sense. It’s just a game with 79 numbers. As above, many players will have a slightly better chance of winning, and getting paid, at the same odds. But some players (perhaps 10%) will have no chance of hitting solid, or winning a substantial amount. This balances out for the game in the long run. On the other hand, the game will tend to hold a higher percentage than expected for long periods of time, since it is the solid hits that determine the day to day percentage of the game.

Experienced keno employees, both supervisors and writers, know when there is a broken or cracked ball in the goose; they can hear it, it sounds different. And, if a Keno supervisor is on the "ball" so to speak, he or she will notice that a ball has not come up for a while. After all, they can call up a frequency report at will, and should do it as a matter of course if the balls have been changed recently.

With a computerized system, it seems to me to be a fairly simple task to build in one or more statistical tests, perhaps based on a binomial or chi-square analysis, that would indicate when the ball selection seems to be non-random. Perhaps such a function would disable the game until the balls were physically checked and verified by someone independent of the game. Just another step towards keeping the gaming business honest.

If you have a keno question that you would like answered, please write to me care of this paper, or contact me on the web via email at kenolil@math.net. Well, that’s it for now. Good luck! I’ll see you in line!